Function CreateTwoVectorFrame

src/celengine/parseobject.cpp:1538–1612

static TwoVectorFrame*
CreateTwoVectorFrame(const Universe& universe,
                     Hash* frameData,
                     const Selection& defaultCenter)
{
    Selection center = getFrameCenter(universe, frameData, defaultCenter);
    if (center.empty())
        return NULL;

    // Primary and secondary vector definitions are required
    Value* primaryValue = frameData->getValue("Primary");
    if (!primaryValue)
    {
        clog << "Primary axis missing from two-vector frame.\n";
        return NULL;
    }

    Hash* primaryData = primaryValue->getHash();
    if (!primaryData)
    {
        clog << "Bad syntax for primary axis of two-vector frame.\n";
        return NULL;
    }

    Value* secondaryValue = frameData->getValue("Secondary");
    if (!secondaryValue)
    {
        clog << "Secondary axis missing from two-vector frame.\n";
        return NULL;
    }

    Hash* secondaryData = secondaryValue->getHash();
    if (!secondaryData)
    {
        clog << "Bad syntax for secondary axis of two-vector frame.\n";
        return NULL;
    }

    // Get and validate the axes for the direction vectors
    int primaryAxis = getAxis(primaryData);
    int secondaryAxis = getAxis(secondaryData);

    assert(abs(primaryAxis) <= 3);
    assert(abs(secondaryAxis) <= 3);
    if (primaryAxis == 0 || secondaryAxis == 0)
    {
        return NULL;
    }

    if (abs(primaryAxis) == abs(secondaryAxis))
    {
        clog << "Bad two-vector frame: axes for vectors are collinear.\n";
        return NULL;
    }

    FrameVector* primaryVector = CreateFrameVector(universe,
                                                   center,
                                                   primaryData);